Strain gauge



FIG. 1 is a top plan view of a strain gauge, showing our new design;

FIG. 2 is a rear view thereof;

FIG. 3 is a right side view thereof; and,

FIG. 4 is a left side view thereof.

The broken lines and the uneven-length broken lines shown in the drawings represent portions of the strain gauge that form no part of the claimed design. All sides not shown form no part of the claimed design. 

CLAIM The ornamental design for a strain gauge, as shown and described. 